A health-conscious octogenarian ended up with an acute kidney injury after his antioxidant diet of almond milk, nuts, tomato paste and vitamin C led to a rare case of calcium oxalate nephropathy, US doctors report.

After reading extensively about the role of diet and supplements in helping prevent cancer and treat diabetes, the 81-year-old downed a litre or more of almond milk each day in addition to wheat germ, “many other nuts” and vitamin C, doctors from Allegheny Health Network in Pittsburgh write.

A discovery that his prostate was enlarged saw him referred to the nephrology clinic with a three-month history of significantly increased creatinine levels (1.5-1.9mg/dL).

The cause for the kidney injury remained unclear but a subsequent referral to urology left the man, who’d had type 2 diabetes for 30 years, “increasingly concerned” about prostate health.